Explain main difficulty during preparation samples and thresholds of processing.

1. Cryostat Tissue Sectioning Problems
Presented by
Dr. Hadeel Khalaf Alboaklah
Dr. Muntader Mohammed Kani

2. Troubleshooting Cryostat Tissue
Sectioning Problems
 Anyone working with a cryostat to make thin
frozen tissue sections will have encountered
some sort of obstacle. Issues like tissue
cracking, freeze artifacts, and curled tissue
slices are commonly experienced but can be
easily troubleshooted. In this week’s article, we
would like to help focus on solving common
problems associated with cryostat-produced
tissue sections for research and clinical studies.

3. Common cryostat problems (& how to
fix them!):
 Tissue folding or curling.
This is one of the most common problems!
Basically, frozen tissue slices curl as it is cut.
To battle this problem, use a fine tissue
paintbrush to gently flatten the curled tissue.
Make sure that your cutting blade is sharp, and
it may help to change out your cutting blade.
You can also use an anti-roll plate, which is a
glass slide that fits right over the cutting stage,
and allows the cut tissue to stay flattened as it
is cut.

4. Tissue cracking
 Tissue cracking. Cracked tissue is
usually from over-freezing the
embedded tissue sample. For
cryostats that have two compressors,
both the freeze chamber and the
specimen holder temperatures can
be controlled. How to solve this
problem? Check your cryostat
temperature and make sure it’s not
too cold. Adjust the temperature by
increasing it 5-degree until you no
longer get tissue cracks in your
sections.

5. Tissue smudges or streaks
 Tissue smudges or streaks. If you see line
streaks vertically across your tissue
slice, check your cutting blade carefully.
Sometimes frozen debris or OCT is stuck
on the blade and can cause streaks.
Clean the cutting blade, or move the
blade to a new section for cutting.
Sometimes you may need to replace the
blade.

6. Tissue sticks to the brush or rips.
 Tissue sticks to the brush or rips.
This usually happens because the user is pulling the
frozen tissue slice. When you use a fine tissue
brush, make sure to roll the brush instead of
tugging. In addition, make sure you are using a
tissue brush with fine bristles, and that the tissue
slice is not getting caught between the bristles.

7. Tissue is not sticking to the glass slide.
 Tissue is not sticking to the glass slide.
When you are ready to mount your frozen tissue
section, you can take a glass slide and touch the
surface to the tissue. The tissue will usually adhere
to the glass slide and the OCT will melt. If you are
not getting this result, it could be that the
temperature of the glass slide is too low, or the
glass slides have been kept inside the freeze
chamber. The temperature difference is what allows
the tissue to stick to the slide when you try to

8. Chuck (specimen holder) is stuck
 Chuck (specimen holder) is stuck. Oh no! If
the chuck you are using gets stuck on the
specimen holder clamp, use 70% ethanol to
clean and unfreeze it. The stuck chuck is
usually caused by small amounts of water
being trapped inside the specimen holder
clamp. You can also run a defrost cycle to
unfreeze the chuck.

9. Cryostat Tutorial